Your church may be approached in the near future by a donor (probably a relatively young person) who wants to make a contribution using "bitcoin." What is bitcoin? Bitcoin is a popular "virtual currency" created for use in commerce. It is not a government-based currency. It might be appropriate to view bitcoin as something akin to frequent-flyer points that can be transferred freely in commerce in payment of obligations.
According to Wikipedia, bitcoin is:
an open source peer-to-peer electronic money and payment network introduced in 2009 by pseudonymous developer "Satoshi Nakamoto." Bitcoin has been called a cryptocurrency because it uses cryptography to secure transactions. Digitally signed payment messages are broadcast to and verified by a decentralized network of computers all over the world. Specialized computers use a proof-of-work system to prevent people from copying and spending the same bitcoin multiple times, a problem for digital currencies known as double-spending. The operators of these computers, known as "miners," are rewarded with transaction fees and newly minted bitcoins.
In order to transact business with bitcoin, the payor and payee must generally have virtual "wallets" (accounts). Coinbase is one company offering such a service. So, in order to accept a contribution of bitcoin, a church would need to establish a bitcoin account and have the transfer made to that account. Bitcoin may be converted to cash (U.S. dollars) by selling it using custodians such as Coinbase.